OK. First of all lets set the scene:
In the Intel SS4200 NAS box 4 drives have been installed (2TB each) in a RAID5 architecture. Worked for a while as a samba server, then problems started with the hardware. We decided to change hardware completely.
So: I built an ubuntu 9.04 server on an intel motherboard. I used one ATA drive for the root filesystem and the 4 PREVIOUS HDDs each one connected to each sata controller.
uname -a reports
Linux NAS 2.6.28-17-server #58-Ubuntu SMP Tue Dec 1 19:58:28 UTC 2009 i686 GNU/Linux
The RAID5 architecture was detected and rebuilt.
Now /sbin/mdadm --detail /dev/md0 reports
root@NAS:/etc# /sbin/mdadm --detail /dev/md0
Version : 00.90
Creation Time : Wed Jan 27 22:06:31 2010
Raid Level : raid5
Array Size : 5860535808 (5589.04 GiB 6001.19 GB)
Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Mon Feb 1 00:11:26 2010
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
UUID : 42dcb4dd:20227bfb:cced5de7:ca715931 (local to host NAS)
Events : 0.44
Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 8 33 1 active sync /dev/sdc1
2 8 49 2 active sync /dev/sdd1
3 8 65 3 active sync /dev/sde1
(NOTE: The physical order of the drives have been changed since the mobo itself has been changed. However I assume that since the Superblock is persistent this did NOT corrupt the data...Please correct me if I am wrong with this....)
Now I discovered that Intel SS4200 box has probably installed an lvm2 volume on top of raid:
Reading all physical volumes. This may take a while...
Found volume group "md0Container" using metadata type lvm2
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
md0Region md0Container -wi-a- 5.46T
PV VG Fmt Attr PSize PFree
/dev/md0 md0Container lvm2 a- 5.46T 0
root@NAS:/etc# fdisk -l /dev/md0
Disk /dev/md0: 6001.1 GB, 6001188667392 bytes
2 heads, 4 sectors/track, 1465133952 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk identifier: 0x00000000
Disk /dev/md0 doesn't contain a valid partition table
...I don't know if this constitutes a problem or not....)
Now I tried to mount the lvm2 volume:
root@NAS:/etc# mount /dev/md0Container/md0Region /mnt
mount: wrong fs type, bad option, bad superblock on /dev/mapper/md0Container-md0Region,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
[97848.417567] EXT4-fs warning (device dm-0): ext4_fill_super: extents feature not enabled on this filesystem, use tune2fs.
[97848.417577] EXT4-fs: dm-0: couldn't mount because of unsupported optional features (2000000).
I tried to
tune2fs -O ^extents /dev/md0Container/md0Region ( I don't know if this is the correct command or not...)
root@NAS:/etc# tune2fs -l /dev/md0Container/md0Region
tune2fs 1.41.9 (22-Aug-2009)
tune2fs: Filesystem revision too high while trying to open /dev/md0Container/md0Region
Couldn't find valid filesystem superblock.
I tried almost everything:
mke2fs -t ext4 -n /dev/md0Container/md0Region
mke2fs 1.41.9 (22-Aug-2009)
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
366288896 inodes, 1465131008 blocks
73256550 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=0
44713 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
102400000, 214990848, 512000000, 550731776, 644972544
root@NAS:/etc# e2fsck -b 98304 /dev/md0Container/md0Region
e2fsck 1.41.9 (22-Aug-2009)
e2fsck: Bad magic number in super-block while trying to open /dev/md0Container/md0Region
The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>
THIS HAPPENS WITH ALL BLOCKS !!!
I TRIED EVERYTHING I KNOW:
root@NAS:/etc# dumpe2fs /dev/md0Container/md0Region
dumpe2fs 1.41.9 (22-Aug-2009)
dumpe2fs: Filesystem revision too high while trying to open /dev/md0Container/md0Region
Couldn't find valid filesystem superblock.
...and I don't know any other way to recover the freaking volume.
What I would like to do is somehow to recover the files that have been written to the volume when the disks were still on Intel SS4200 NAS box.
Any help would be greatly appreciated.
Many Thanks to all!